Celebrating Mass Sept. 8 in Villavicencio, a city filled with those who fled their homes during the war and with former fighters trying to start over, Pope Francis pleaded for honesty and courage.

At the beginning of the Mass, he held up two heroic examples of those who gave their lives to "rise up out of the swamp of violence and bitterness": Bishop Jesus Emilio Jaramillo Monsalve of Arauca, who was murdered by Colombian Marxist guerrillas in 1989, and Father Pedro Maria Ramirez, who was killed at the start of the Colombian civil war in 1948.

Pope Francis beatified the two at the Mass, which was celebrated in the middle of a broad field, typical of the area's cattle ranching terrain.

In his homily, the Pope acknowledged that, during 52 years of war, many at the Mass suffered horrors.

"How many of you can tell of exiles and grief," he said.

The Christian call to reconciliation is not something abstract, the Pope said. "If it were, then it would only bring sterility and greater distance." It requires acknowledging the truth and letting victims speak.

And "when victims overcome the understandable temptation to vengeance, they become the most credible protagonists for the process of building peace," he said. "What is needed is for some to courageously take the first step in that direction, without waiting for others to do so. We need only one good person to have hope. And each of us can be that person.

"This does not mean ignoring or hiding differences and conflicts. This is not to legitimize personal and structural injustices," Pope Francis insisted. Reconciliation must be accompanied by a firm commitment to change the inequalities and behaviors that fueled the war for decades.

Celebrating Mass in an area known as the gateway to the Amazon, the Pope said he could not ignore the need for reconciliation with the natural environment.

"It is not by chance that even on nature we have unleashed our desire to possess and subjugate," he said. To the delight of many in the crowd, he quoted the famous Colombian singer and peace activist, Juanes: "The trees are weeping, they are witnesses to so many years of violence. The sea is brown, a mixture of blood and earth."